Video data is typically composed of a series of still images which are shown rapidly in succession as a video sequence to give the idea of a moving image. Video applications are continuously moving towards improved image resolution (greater number of pixels per frame, higher frame rate, higher bit-depth . . . ). A large quantity of video content is distributed in digital form via broadcast channels, digital networks and packaged media, with a continuous evolution towards improved quality and resolution (e.g. higher number of pixels per frame, higher frame rate, higher bit-depth or extended colour gamut). This evolution in technology puts increased pressure on distribution networks that already face difficulties in providing HDTV resolution and data rates economically to the end user. Consequently, further increases in data rate will put additional pressure on such distribution networks. To address this challenge, ITU-T (International Telecommunications Union, telecommunications Standardization Sector) and ISO/MPEG decided to launch a new video coding standard project in January 2010, known as High Efficiency Video Coding (HEVC).
HEVC codec design is similar to that of most previous so-called block-based hybrid transform codecs such as H.263, H.264, MPEG-1, MPEG-2, MPEG-4, SVC. Video compression algorithms, such as those standardized by the standardization bodies ITU, ISO and SMPTE, use spatial and temporal redundancies of images in order to generate data bit streams of reduced size. Spatial redundancy represents the mutual correlation between adjacent image pixels, while temporal redundancy represents the correlation in image objects in sequential images. Such compression processes make the transmission and/or storage of video sequences more effective.
Video sequences encoded by HEVC are used in many applications such as streaming environments or lightweight performance devices. In order to be more robust to streaming errors and to be able to process data in parallel in lightweight devices, for example, new coding structures and rules have been added to HEVC. However, current HEVC techniques do not provide a solution that is flexible enough to respond to requirements of all of these applications efficiently.